THERMAL APPLICATIONS NOTE Polymer Heats of Fusion

THERMAL APPLICATIONS NOTE

Polymer Heats of Fusion

Roger L. Blaine TA Instruments,109 Lukens Drive, New Castle DE 19720, USA

The heat of fusion of 100 % crystalline polymer is required to obtain percent crystallinity by differential scanning calorimetry (1). Polymer reference materials with 100 % crystallinity are rarely available for comparison purposes. Fortunately, the heats of fusion values for 100 % crystalline polymers may be determined by indirect methods such as extrapolation using the Flory equation (2). Wunderlich and co-workers (3) have created tables of best estimate values for the heats of fusion for a wide variety of linear polymers with values reported in joules per mole of repeat unit. To be useful for thermal analysis purposes, these enthalpy values need to be normalized to mass. Table 1 includes the mass normalized enthalpy of fusion values commonly used in DSC determinations.

REFERENCES

1. TA123, “Determination of Polymer Crystallinity by DSC”, TA Instruments, New Castle, DE. 2. TA276, “Determination of Polymer Crystal Molecular Weight Distribution by DSC”, TA Instruments, New Castle, DE. 3. B. Wunderlich, Thermal Analysis, Academic Press, 1990, pp. 417-431. 4. D1600, “Abbreviated Terms Relating to Plastics”, American Society for Testing and Materials, West Conshohocken, PA.

KEYWORDS

differential scanning calorimetry, melting, thermoplastic polymers

1 TN048 Table 1 – Polymer Heats of Fusion

Acronym Name Enthalpy Repeat Unit Molecular Enthalpy (4) (kJ/mol) Weight (J/g) (3) (g/mol)

PE Polyethylene 4.11 -CH2- 14.03 293

PP Polypropylene 8.70 -CH2CH(CH3)- 42.08 207 PB Polybutene-1 7.00 -CH2CH(C2H5) 56.1 125

POM Polymethylenoxide 9.79 -CH2O- 30.03 326

PEOX Polyethyleneoxide 8.66 -CH2CH2O- 44.05 197

PA6 Polycaprolactam 26.0 -NH(CH2)5CO- 113.2 230

PA11 Polyundecanolactam 44.7 -NH(CH2)10CO- 183.3 244

PA12 Polylauryllactam 48.4 -NH(CH2)11CO- 197.3 245

PA66 Poly(hexamethylene adipamide) 57.8 -NH(CH2)6NHCO(CH2)4CO- 256.3 226

PA69 Poly(hexamethylene nonanediamide) 69 -NH(CH2)6NHCO(CH2)7CO- 268.4 257

PA610 Poly(hexamethylene sebacamide) 71.7 -NH(CH2)6NHCO(CH2)8CO- 282.4 254

PA612 Poly(hexamethylene dodecanediamide) 80.1 -NH(CH2)6NHCO(CH2)10CO- 310.5 258

PVOH Polyvinyl alcohol 7.11 -CH2CH(OH)- 44.05 161

PET Polyethylene terephathalate 26.9 -O(CH2)2O2CC6H4CO- 192.2 140

PBT Polybutylene terephathalate 32.0 -O(CH2)4O2CC6H4CO- 220.2 145

PVF Polyvinyl fluoride 7.54 -CH2CH(F)- 46.04 164

PVDF Polyvinylidene fluoride 6.70 -CH2CF2- 64.03 105

Polytrifluoroethylene 5.44 -CH(F)CF2- 82.0 66.3

PTFE Polytetrafluoroethylene 4.10 -CF2- 50.0 82.0

PVC Polyvinyl chloride 11.0 -CH2CH(Cl)- 62.50 176 PCTFE Polychlorotrifluoroethylene 5.02 -CF2CF(Cl)- 116.5 43.1 PEEK Polyetheretherketone 37.4 -C6H4COC6H4OC6H4O- 288.3 130

2 TN048